Culminating Project Title
Date of Award
Culminating Project Type
Biological Sciences - Cell and Molecular: M.S.
College of Science and Engineering
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Keywords and Subject Headings
Complex mixtures, multi-generational, fathead minnows, life-cycle, environmental, nitrate
More than one-third of the Earth’s freshwater is used for agricultural, industrial, and domestic purposes leading to the frequent co-occurrence of nitrate and mixtures of contaminants of emerging concerns in aquatic ecosystems. However, little is understood about the consequences of life-cycle exposure of fishes to these complex environmental mixtures. This project examined changes in physiology, performance, and reproduction in fathead minnows across three generations of exposure to agricultural and urban mixtures at environmentally relevant concentrations with an added stressor of nitrate. Exposure of adult fathead minnows in the first, but not second, generation to high nitrate concentrations resulted in a two-fold increase in egg production. In the second generation, the agricultural mixture enhanced fecundity in female fathead minnows above levels observed in EtOH control fish. Contrary to some published studies, neither nitrate nor estrogenic agricultural mixtures stimulated vitellogenin production in male fishes. In contrast, feminization (presence of the egg-yolk protein vitellogenin) was found in first generation males following exposure only to an urban chemical mixture independent of nitrate concentrations. Adult behavior does not appear to be affected regardless of treatment and generation. In contrast, larval behaviors, including predator avoidance performance and foraging efficiency, were both improved in higher nitrate treatments. Using an extended life-cycle fathead minnow exposure, we were able to improve our understanding of the consequences associated with long-term exposures to complex environmental mixtures. Overall, the observed effects of environmentally realistic mixtures were subtle and did neither follow a clear dose-response or matched effects observed in single compound exposures in the published literature. The complexity of interactions between multiple pollutant stressors observed in the current study highlight the need for additional such studies to ensure adequate assessment of environmental risk.
King, Chryssa, "Life Cycle Exposure of Fathead Minnows to Complex Environmental Mixtures" (2020). Culminating Projects in Biology. 47.